firefox6 font kerning is just plain weird and unacceptable

[-ck-]

What the heck is with the crazy font kerning in Firefox 6?

Using WindowsXP, and I tried messing with all the gfx settings and disabling hardware acceleration, no change)

Try this and look at how letters are shoved underneath the capital T until they hit a certain font size. Then try it in any other browser, including Firefox 3.6



http://jsbin.com/etiyah

Code: Select all

<style>
li {font-family:arial,sans-serif;font-weight:bold; color:navy; padding:0;margin:0; border-bottom:1px dashed #ccc;}
</style>
<ul>
   <li style="font-size:12px">Too Tip Tag Tell Tye</li>
   <li style="font-size:14px">Too Tip Tag Tell Tye</li>   
   <li style="font-size:16px">Too Tip Tag Tell Tye</li>
   <li style="font-size:18px">Too Tip Tag Tell Tye</li>
   <li style="font-size:20px">Too Tip Tag Tell Tye</li>
   <li style="font-size:22px">Too Tip Tag Tell Tye</li>   
   <li style="font-size:24px">Too Tip Tag Tell Tye</li>   
   <li style="font-size:26px">Too Tip Tag Tell Tye</li>      

</ul>   

[-ck-]

Ah, I finally discovered

gfx.font_rendering.harfbuzz.scripts

Setting from 3 to 0 seems to have solved it and it kerns like 3.6 (and every other browser) now.

The word "scripts" threw me off.

Now trying to understand what each level means.

Found this mention of harfbuzz but level 3 isn't listed:

https://wiki.mozilla.org/Platform/2010-06-15#GFX_Update

[AhamB]

Wow, I noticed this bug too, but how does Mozilla keep introducing "features" like this and enable them by default (fuzzy font rendering anyone)?
Anyway, thanks for posting the solution!

[bzbarsky]

Now trying to understand what each level means.

They aren't levels. They're bitmasks indicating which shaping types to use harfbuzz for. The default pref setting is:

Code: Select all

208 // use harfbuzz for default (0x01) + arabic (0x02)
209 pref("gfx.font_rendering.harfbuzz.scripts", 3);

So 0 means to disable harfbuzz altogether.

The full list of shaping types is

Code: Select all

68     enum ShapingType {
69         SHAPING_DEFAULT   = 0x0001,
70         SHAPING_ARABIC    = 0x0002,
71         SHAPING_HEBREW    = 0x0004,
72         SHAPING_HANGUL    = 0x0008,
73         SHAPING_MONGOLIAN = 0x0010,
74         SHAPING_INDIC     = 0x0020,
75         SHAPING_THAI      = 0x0040
76     };

[bzbarsky]

I filed https://bugzilla.mozilla.org/show_bug.cgi?id=690806 on this.

[-ck-]

Thanks bzbarsky - and for those that care, the problem persists even under Firefox 10.0 final